Posted by Aaron Barton on Mar 4th 2023
Perfect for transitioning spring gardens into the heat of summer, Amsonia, or bluestar, of the dogbane family, Apocynaceae, is a prolific bloomer offering multi-season interest, ideal for sunny borders, cottage gardens, and woodland gardens, and stunning when used in mass plantings.
Native to open woods and moist meadows across central and eastern North America, bluestar is a hardy, low maintenance perennial, tolerant of a range of site conditions. Most ornamental Amsonia varieties are cultivars of Amsonia tabernaemontana (Am-SO-nee-ah tab-er-nay-mon-TAY-nah), commonly known as willow, eastern, or woodland bluestar.
Blooming in late spring through early summer, Amsonia emerges as a lush multi-stemmed cluster of fine green foliage, typically reaching a mature size of 18-36” round. Providing nearly four weeks of color in the garden, bluestar produces abundant terminal clusters of ¾” wide, tubular light blue flowers from fuzzy buds, excellent for hummingbirds, moths, and other nectar-feeding pollinators, and great as long-lasting cut flowers. After blooming, each pollinated flower develops into a pair of four-to six-inch-long cylindrical seed pods for continued interest into the summer months.
Preferring moist, well-drained soils and drought tolerant once established because of their large taproot, Amsonia thrives in full or part sun, though bluestar planted in overly shaded sites may be prone to bending or flopping. Overfertilization can also exaggerate this open, flopping habit and should be avoided. If desired, plants may be trimmed after blooming by one third up to one half their total size to prevent flopping and promote dense, bushy growth at the expense of their showy seed pods, however care should be taken when trimming as Amsonia contain an irritating latex sap, making them undesirable to deer and rabbits as well. Amsonia continue to provide color and interest late into the season, taking on striking golden-amber color well into the fall.
Bluestar is available in many cultivars, including the popular dark stems, silver-veined foliage, and periwinkle blooms of ‘Storm Cloud,’ and the more compact habit and darker blue blooms of ‘Blue Ice.’